R.R. · Reinhold Ripperger · Reinhold Rupprecht · Ronald G. Roberson
| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Eastern Christian Churches: A Brief Survey | 978-88-7210-177-3 (88-7210-177-8) | 1990 |
| The Eastern Christian Churches: A Brief Survey | 978-88-7210-321-0 (88-7210-321-5) | 1999 |